Disease Control

NOTES: For the disease control products listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same active ingredient. Please see Table 26 and Fungicides and Bactericides Alphabetical Listing by Trade Name for more information on products with the same active ingredients.

The symbol ^OG   indicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more details.

Anthracnose Leaf Curl (Colletotrichum fioriniae and C. nymphaeae)

Celery anthracnose caused by Colletotrichum fioriniae and C. nymphaeae (formerly C. acutatum). C. fioriniae also causes bitter rot in apples while C. nymphaeae  causes anthracnose of strawberries and garlic scapes. Symptoms on celery include curled leaves, occasional discoloration of leaf margins, twisted petioles, and lesions on petioles. Leaves remain green but often appear fan-like and curl downward.  Leaf curl is often the most prominent symptom observed and can resemble injury from growth regulator type (e.g. 2,4-D) herbicides. In advanced stages, the disease can resemble blackheart, the physiological disorder caused by low calcium assimilation. Celery leaf curl thrives under warm, wet conditions. Rapid growth occurs when temperatures are 77-86°F, with substantially more disease development at 86ºF. Temperatures as cool as 60°F will support fungal growth and spread, but field progression will be slow. This disease may be seedborne. Start with clean seed, flats, and growing media. Plant tolerant varieties. Avoid planting in fields with a history of strawberry or garlic anthracnose. Scout plants twice a week for symptoms; remove and destroy affected plants. Manage weeds, several common species harbor celery anthracnose without clearly expressing symptoms. Remove crop debris after harvest and/or plowing crop residue. A 3 to 4 year crop rotation with non-host plants should be followed. Avoid working the fields when the plants are wet, work in fields with a history of the disease last, and power wash equipment between fields. Research has shown that the strobilurin fungicides are most effective; however, be careful to rotate as resistance can develop quickly in this group.

• azoxystrobin (Quadris): 6.0 to 15.5 fl oz/A; PHI 0d, REI 4h, Group 11. Do not apply more than one application before alternating with a non-Group 11 fungicide.
• flutriafol (Rhyme): 5.0 to 7.0 fl oz/A; PHI 7d, REI 12h, Group 3. Apply preventatively when conditions are favorable for disease development.
• pyraclostrobin (Cabrio EG): 12-16 oz /A; PHI 0d, REI 12h , Group 11. Do not apply more than one application before alternating with a non-Group 11 fungicide. Apply no more than 64 oz per year.
• pyraclostrobin plus boscalid (Pristine): 10.0 to 15.0 oz/A; PHI 0d, REI 12h, Groups 11 & 7. Maximum of 2 applications per year.
• pyraclostrobin plus fluxapyroxad (Merivon Xemium): 4.0 to 11.0 fl oz/A; PHI 1d, REI 12h, Groups 11 & 7. Maximum of 3 applications per year.

Leaf Blight (Cercospora apii (Early Blight) and Septoria apicola (Late Blight))

The primary symptom of early blight (Cercospora apii) is the occurrence of small yellow spots that are visible from both sides of the leaf. These spots may develop into larger lesions that become papery and often tear. Gray, fuzzy fungi may be visible in well-developed lesions. Favorable temperatures for early blight range from 60-86ºF. This pathogen can be seedborne, can survive on celery crop residue, and spores can spread via wind and water splashing.

Small, yellow, circular spots on leaves are also symptoms of late blight (Septoria apicola) in celery, which has similar symptoms to early blight in celery overall. One difference is that the small, round, and dark reproductive bodies of late blight, called pycnidia, can be seen in the center of lesions. This pathogen develops when temperatures are greater than 55ºF, and particularly in wet conditions when temperatures exceed 70ºF.

Use certified, disease-free seed or treat seed with hot water or fungicides. Practice careful sanitation in transplant greenhouses or rotate ground seedbeds. Irrigate early in the day to allow foliage to dry quickly. Use wider plant spacing and/or raised beds to improve air circulation. Plant resistant or tolerant varieties where available. Apply fungicides based upon a disease forecasting system.

• azoxystrobin (Quadris F): 6.0 to 9.0 fl oz/A; PHI 0d, REI 4h, Group 11. Do not apply more than one application before alternating with a non-Group 11 fungicide.
• azoxystrobin plus chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M05. See label for tank mix precautions.  
• azoxystrobin plus propiconazole (Quilt Xcel): 14.0 fl oz/A; PHI 14d, REI 12h, Groups 11 & 3. 
• bacillus amyloliquefaciens F727 (Stargus^OG): 2.0 to 4.0 qt/A; PHI 0d, REI 4h, Group BM02. See label for specific instructions.
• chlorothalonil (Bravo Weather Stik): 2.0 to 3.0 pt/A; PHI 7d, REI 12h, Group M05.
• copper hydroxide (Kocide 3000OG): 0.75 to 1.5 lb/A; PHI 0d, REI 48h, Group M01. Do not apply in a spray solution having a pH of less than 6.5 or tank mix with Aliette.
• cyprodinil plus fludioxonil (Switch 62.5 WG): 11.0 to 14.0 fl oz/A; PHI 0d, REI 12h, Groups 9 & 12.
• fluxapyroxad plus pyraclostrobin (Merivon): 4.0 to 11.0 fl oz/A; PHI 1d, REI 12h, Groups 7 & 11.
• penthiopyrad (Fontelis): 14.0 to 24.0 oz/A; PHI 3d, REI 12h, Group 7.
• propiconazole (Tilt): 4.0 fl oz/A; PHI 14d, REI 24h, Group 3.
• pyraclostrobin plus boscalid (Pristine): 10.0 to 15.0 oz/A; PHI 0d, REI 12h, Groups 7 & 11. Maximum 2 applications per year. 
• pydiflumetofen plus fludioxonil (Miravis Prime): 9.2 to 13.4 fl oz/A; PHI 0d, REI 12h, Groups 7 & 12. 
• trifloxystrobin (Flint): 2.0 to 3.0 oz/A; PHI 7d, REI 12h, Group 11. Do not make more than one application before alternating with a non-Group 11 fungicide.

Fusarium Yellows (Fusarium oxysporum f.sp. apii)

Fusarium yellows causes yellowing of outer leaves, stunting, and eventually death.  This pathogen spreads through plants’ vasculature, and infection may be spotty within fields as symptoms are commensurate with the degree of infection.  While this pathogen only infects celery, its spores can remain in soil almost indefinitely, surviving on celery crop residues, non-host crops, and many weed species.  Once a field is infected, only resistant varieties can be grown.  Rotating an infected field to onion or lettuce production for two years, before the pathogen becomes seriously problematic, is recommended to allow for spore decline.  Good equipment and worker sanitation can reduce spread.  Source resistant varieties and disease-free transplants.  As with other fungal pathogens, avoid working fields when wet.

Basal Stalk Rot (Rhizoctonia solani)

Rhizoctinia in celery is sometimes called crater rot, or simply stalk rot. This pathogen causes symptoms on petioles when they are in contact with the soil. Symptoms include reddish brown lesions on either side of the petiole, and can become sunken. This pathogen is soilborne and infects many plants. It is favored by warm, humid/wet conditions, and can survive in soil as sclerotia for a long time.

A 2-year rotation is can prevent buildup of disease-causing organisms.  Avoid crops such as alfalfa and legume cover crops which can increase disease risk.  Avoid cultivating late in the season. Maintain storage conditions at 50°F.

• azoxystrobin (Quadris):  0.4 to 0.8 fl oz/1,000 row feet; PHI 0d, REI 4h, Group 11 (see label for clarification). Apply in a 7" band in-furrow or shortly after emergence.  After emergence, direct application to stem.
• azoxystrobin plus chlorothalonil (Quadris Opti): 2.4 to 3.7 pt/A; PHI 7d, REI 12h, Groups 11 & M5. See label for tank mix precautions.  
• Bacillus amyloliquefaciens F727 (Stargus^OG): 1.0 to 4.0 qt/A; PHI 0d, REI 4h, Group BM02. Apply preventatively in a minimum of 50.0 gallons/A. 
• chlorothalonil (Bravo Weather Stik): 2.0 to 3.0 pt/A; PHI 7d, REI 12h, Group M05.
• polyoxin D (OSO 5%SC^OG): 6.5 to 13.0 fl oz/A; PHI 0d, REI 4h, Group 19.

Pink Rot (Sclerotinia sclerotiorum)

Pink rot in celery is caused by the same pathogen that causes white mold  in beans and peas. This pathogen can infect celery at any developmental stage, but is most commonly seen near harvest. The most characteristic symptoms are lesions on the lower portion of petioles that are initially brown and then turn water-logged, slimy, and pink. Lesions can contain white mycelia and/or hardened black sclerotia. Severely infected plants may totally collapse. Infections can go unnoticed, especially on inner petioles. Symtpoms can also appear during storage. Do not plant seed contaminated with sclerotia or plant into severely infested fields. Irrigate in the morning or with subsurface drip systems to promote drier soil. Rotate with non-hosts. Soil sterilization with chemicals, heat, or steam can reduce sclerotia in the soil.

• Bacillus amyloliquefaciens F727 (Stargus^OG): 1.0 to 4.0 qt/A; PHI 0d, REI 4h, Group BM02. Apply preventatively in a minimum of 50.0 gallons of water/A.
• boscalid (Endura): 8.0 to 9.0 oz/A; PHI 0d, REI 12h, Group 7.
• chlorothalonil (Bravo Weather Stik): 3.0 pt/A; PHI 7d, REI 12h, Group M05. For disease suppression.
• Coniothyrium minitans (Contans WG^OG): 1.0 to 4.0 lb/A in 20.0-50.0 gal water; REI 4h, Group BM02. Spray on soil surface and incorporate into top 2" soil. Apply in fall or 3-4 months prior to planting.
• cyprodonil plus fludioxonil (Switch 62.5 WG): 11.0 to14.0 oz/A; PHI 0d, REI 12h, Groups 9 & 12. Make first application at thinning and once more two weeks later.
• pyraclostrobin plus boscalid (Pristine): 25.0 oz/A; PHI 0d, REI 12h, Groups 7 & 11. Maximum 2 applications per year. 
• Ulocladium oudemansii (BotryStop^OG): 2.0 to 4.0 lbs/A; REI 4h, Group BM02. Begin application when conditions are conducive to disease development.